/* ============================================================
   黑色服务 - 极简暗黑风格 v3.1
   简单、简约、神秘
   ============================================================ */

:root {
    --bg: #000000;
    --bg-subtle: #0f0f0f;
    --border: #222222;
    --border-hover: #333333;
    --text: #e8e8e8;
    --text-dim: #b0b0b0;
    --text-bright: #ffffff;
    --accent: #00cc66;
    --accent-dim: #00aa55;
    --font-mono: "SF Mono", "Fira Code", "Cascadia Code", "JetBrains Mono", "Consolas", "Monaco", monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    scrollbar-width: thin;
    scrollbar-color: var(--border) var(--bg);
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-mono);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

::selection {
    background: rgba(0, 204, 102, 0.15);
    color: var(--accent);
}

::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); }

a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== Nav ===== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 20px 0;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
}

.nav .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    font-size: 1.25rem;
    color: var(--text-bright);
    letter-spacing: 0.1em;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    font-size: 0.875rem;
    color: var(--text-dim);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--accent);
}

.nav-blog {
    color: var(--accent) !important;
}

/* ===== Hero ===== */
.hero {
    min-height: 100dvh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 120px 24px 80px;
}

.hero-inner {
    max-width: 600px;
}

.hero-tag {
    font-size: 0.8125rem;
    color: var(--accent-dim);
    letter-spacing: 0.2em;
    text-transform: uppercase;
    margin-bottom: 40px;
}

.hero-tag::before {
    content: '> ';
    color: var(--text-dim);
}

.hero h1 {
    font-family: var(--font-sans);
    font-size: 2.5rem;
    font-weight: 300;
    color: var(--text-bright);
    line-height: 1.4;
    margin-bottom: 32px;
    letter-spacing: -0.02em;
}

.hero-desc {
    font-size: 1rem;
    color: var(--text-dim);
    line-height: 1.8;
    margin-bottom: 48px;
}

.hero-line {
    width: 40px;
    height: 1px;
    background: var(--border);
    margin: 0 auto;
}

/* ===== Section ===== */
.section {
    padding: 120px 0;
    border-top: 1px solid var(--border);
}

.section-label {
    font-size: 0.8125rem;
    color: var(--text-dim);
    letter-spacing: 0.2em;
    text-transform: uppercase;
    margin-bottom: 60px;
}

.section-label::before {
    content: '// ';
    color: var(--accent-dim);
}

/* ===== Services ===== */
.service-list {
    display: flex;
    flex-direction: column;
}

.service-item {
    padding: 32px 0;
    border-bottom: 1px solid var(--border);
    display: grid;
    grid-template-columns: 40px 1fr;
    gap: 24px;
    align-items: start;
    transition: background 0.3s;
    cursor: default;
}

.service-item:first-child {
    border-top: 1px solid var(--border);
}

.service-item:hover {
    background: var(--bg-subtle);
}

.service-item:hover .service-name {
    color: var(--text-bright);
}

.service-num {
    font-size: 0.8125rem;
    color: var(--text-dim);
    padding-top: 4px;
}

.service-content {}

.service-name {
    font-family: var(--font-sans);
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--text);
    margin-bottom: 8px;
    transition: color 0.3s;
}

.service-desc {
    font-size: 0.9375rem;
    color: var(--text-dim);
    line-height: 1.7;
}

/* ===== About ===== */
.about-text {
    max-width: 560px;
}

.about-text p {
    font-size: 1rem;
    color: var(--text-dim);
    line-height: 2;
    margin-bottom: 20px;
}

.about-text p:last-child {
    margin-bottom: 0;
}

/* ===== Contact ===== */
.contact-list {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.contact-item {
    padding: 24px 0;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.contact-item:first-child {
    border-top: 1px solid var(--border);
}

.contact-label {
    font-size: 0.8125rem;
    color: var(--text-dim);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    flex-shrink: 0;
}

.contact-value {
    font-size: 1rem;
    color: var(--text);
    text-align: right;
    transition: color 0.3s;
    word-break: break-all;
}

a.contact-value {
    color: inherit;
    text-decoration: none;
}

.contact-item:hover .contact-value {
    color: var(--accent);
}

/* ===== Bottom Nav ===== */
.bottom-nav {
    padding: 80px 0;
    border-top: 1px solid var(--border);
}

.bottom-nav-header {
    margin-bottom: 32px;
}

.bottom-nav-title {
    font-size: 0.8125rem;
    color: var(--text-dim);
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.bottom-nav-title::before {
    content: '// ';
    color: var(--accent-dim);
}

.bottom-nav-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 16px 24px;
}

.bottom-nav-grid a {
    font-size: 0.8125rem;
    color: var(--text-dim);
    letter-spacing: 0.05em;
    transition: color 0.3s;
}

.bottom-nav-grid a:hover {
    color: var(--accent);
}

.bottom-nav-grid a.bottom-nav-url {
    color: var(--accent);
    border-bottom: 1px solid var(--accent-dim);
}

.bottom-nav-grid a.bottom-nav-url:hover {
    color: var(--text-bright);
    border-bottom-color: var(--accent);
}

/* ===== Footer ===== */
.footer {
    padding: 40px 0;
    border-top: 1px solid var(--border);
    text-align: center;
}

.footer p {
    font-size: 0.875rem;
    color: var(--text-dim);
    letter-spacing: 0.05em;
}

/* ===== Back to Top ===== */
.back-to-top {
    position: fixed;
    bottom: 24px;
    right: 24px;
    width: 32px;
    height: 32px;
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-dim);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s, border-color 0.3s, color 0.3s;
    z-index: 99;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.back-to-top svg {
    width: 14px;
    height: 14px;
}

/* ===== Fade ===== */
.fade-in {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Mobile ===== */
@media (max-width: 768px) {
    html { font-size: 15px; }

    .nav { padding: 16px 0; }

    .nav-links { gap: 24px; }

    .nav-links a {
        font-size: 0.875rem;
        padding: 8px 4px;
    }

    .hero {
        padding: 80px 24px 48px;
    }

    .hero h1 { font-size: 2.2rem; }

    .section { padding: 80px 0; }

    .service-item {
        grid-template-columns: 1fr;
        gap: 8px;
    }

    .service-num {
        display: inline;
        margin-right: 8px;
        font-size: 0.8125rem;
        color: var(--accent-dim);
    }

    .service-content {}

    .contact-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 6px;
    }

    .contact-value {
        text-align: left;
    }

    .back-to-top {
        bottom: 16px;
        right: 16px;
        width: 36px;
        height: 36px;
    }

    .bottom-nav { padding: 48px 0; }

    .bottom-nav-header { margin-bottom: 24px; }

    .bottom-nav-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 12px 16px;
    }

    .bottom-nav-grid a { font-size: 0.75rem; }

    .footer p { font-size: 0.875rem; }
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
    .fade-in { opacity: 1; transform: none; }
}